1. Field of the Invention
This invention relates to hydrophilic materials, particularly, to an ambient temperature curable hydrophilic polyurethane (PU) oligomer, a method for synthesizing the same, and a surface treatment method of using the same.
2. Description of the Related Art
There are lots of natural hydrophilic polymers such as starch, cellulose, dextrin, and artificial hydrophilic polymers such as polyethylene glycols (PEG), poly vinyl alcohol (PVA) and etc. Whatever natural or artificial hydrophilic polymers which mentioned before, when they are used in the surface treatment of a textile or a glass (e.g. a car window or mirror), an adhesion thereof will be lost for contacting the water, even more, dissolved in water. Presently, the hydrophilic modifications of textile surface (e.g. polyester and etc.) are mainly based on modified carbohydrate (e.g. dextrin or starch). It is due to only the van der waals force occurring between hydrophilic polymer(s) and textile surface, the hydrophilicity is temporarily achieved. The hydrophilicity will be lost after several washing cycles by water because the conventional hydrophilic polymers will be swollen when they contact with water, even more, be dissolved in water, thereby the hydrophilicity of textile surface can not be maintained. Especially for color printing ink applications, the poly vinyl alcohol (PVA) is coated on the photo-paper or transparent to enhance the hydrophilicity; but PVA becomes slimy when it contacts with water or moisture, so that the images printed on such photo-paper or transparent are destroyed.
All of problems mentioned above are caused by applying the conventional hydrophilic polymers without water resistance. Therefore, a hydrophilic material overcome the above-mentioned problems is desired.